Tamper With Sophos AV Registry Keys — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2022-09-02 / 2023-08-17.

{
  "category": "registry_set",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ec2647c58a64d09088e816fdf631ba27ee00734c29e4f8ebf24acc283802305b

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Tamper With Sophos AV Registry Keys
id: 9f4662ac-17ca-43aa-8f12-5d7b989d0101
status: test
description: Detects tamper attempts to sophos av functionality via registry key modification
references:
    - https://redacted.com/blog/bianlian-ransomware-gang-gives-it-a-go/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-02
modified: 2023-08-17
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains:
            - '\Sophos Endpoint Defense\TamperProtection\Config\SAVEnabled'
            - '\Sophos Endpoint Defense\TamperProtection\Config\SEDEnabled'
            - '\Sophos\SAVService\TamperProtection\Enabled'
        Details: DWORD (0x00000000)
    condition: selection
falsepositives:
    - Some FP may occur when the feature is disabled by the AV itself, you should always investigate if the action was legitimate
level: high

Original YAML and metadata in JSON

False positives

• Some FP may occur when the feature is disabled by the AV itself, you should always investigate if the action was legitimate

Source references

• https://redacted.com/blog/bianlian-ransomware-gang-gives-it-a-go/